參考官方文檔：

https://docs.microsoft.com/zh-cn/sql/t-sql/statements/create-partition-function-transact-sql

默認是Left

LEFT：第一個值屬於第一個表，對應<=

RIGTH: 第一個值屬於第二個表，對應<

如果數據按年進行分區，則RIGHT選項且每年的1月1日是合適的。如：

CREATE PARTITION FUNCTION [myDateRangePF1] (datetime)  
AS RANGE RIGHT FOR VALUES (‘20030101‘, ‘20040101‘);  
這個有三個區：[0，20030101)
 
, [20030101, 20040101), [20040101, 999909999)

Examples

A. Creating a RANGE LEFT partition function on an int column

The following partition function will partition a table or index into four partitions.

CREATE PARTITION FUNCTION myRangePF1 (int)  
AS RANGE LEFT FOR VALUES (1, 100, 1000);  

The following table shows how a table that uses this partition function on partitioning column col1

B. Creating a RANGE RIGHT partition function on an int column

The following partition function uses the same values for boundary_value [ ,...n ] as the previous example, except it specifies RANGE RIGHT.

CREATE PARTITION FUNCTION myRangePF2 (int)  
AS RANGE RIGHT FOR VALUES (1, 100, 1000);  

The following table shows how a table that uses this partition function on partitioning column col1 would be partitioned.

C. Creating a RANGE RIGHT partition function on a datetime column

The following partition function partitions a table or index into 12 partitions, one for each month of a year‘s worth of values in a datetime column.

CREATE PARTITION FUNCTION [myDateRangePF1] (datetime)  
AS RANGE RIGHT FOR VALUES (‘20030201‘, ‘20030301‘, ‘20030401‘,  
               ‘20030501‘, ‘20030601‘, ‘20030701‘, ‘20030801‘,   
               ‘20030901‘, ‘20031001‘, ‘20031101‘, ‘20031201‘);  

The following table shows how a table or index that uses this partition function on partitioning column datecol would be partitioned.

mssqlserver分區表的左值與右值